The success of genetic epidemiology lies in replication of results. To that end, this project draws on the AGES-Reykjavik Study and Health, Aging, and Body Composition Study, both of which have been involved in candidate gene studies and will soon complete genome-wide association studies. The studies share several phenotypes in common - measurement of adipose tissue, muscle area, muscle density, measures of grip and quadricep strength, and assessment of physical functioning. If assoications are replicated in these two studies, we will work with consortia of other epidemiology studies to further reinforce (or refute) our findings.